Sweetness Lab

In this lab, we asked the question, “How does the structure of a carbohydrate affect its taste regarding sweetness?” We found that the monosaccharides were the sweetest, disaccharides were not as sweet, and polysaccharides were the most bland. In our experiment, the monosaccharides that we tested were galactose, fructose, and glucose. The disaccharides were sucrose, maltose, and lactose, and the polysaccharides were cellulose and starch. In the experiment, sucrose was given a rating of 100 in regards to its degree of sweetness, glucose was given a 120, fructose was given a 150, galactose was given a 130, maltose was given a 70, lactose was given a 30, starch was given a 5, and cellulose was given a 2. These results could have come from the research that monosaccharides, since they have just one sugar unit, are sweeter than the polysaccharides or disaccharides with multiple. In addition, monosaccharides are more used and found in sweet foods. This data supported our claim because the monosaccharides that we tasted proved to be sweeter than the disaccharides and polysaccharides that we tasted.

The carbohydrate structure affected how they are used by cells and organisms because since monosaccharides have only 1 ring, they are used in foods. Since disaccharides have 2 rings they are used for energy. Since polysaccharides have 3 or more rings, they are many used to store energy and is used for photosynthesis and is found in cell walls.

In this experiment, not all testers gave each sample the same rating. The testers could have not drank water in between each test, meaning that the sugar could’ve tasted sweeter or more bland than it was supposed to. Everyone has different taste buds, so one sugar would have tasted different for another person. Also the spoons could have been contaminated when tasting the different sugars, mixing many different tastes and therefore giving false results.

According to Dr. Robert Margolskee, what causes humans to taste sweetness is the receptor proteins on the taste cells in the taste buds getting stimulated by something sweet. After it gets stimulated, a signal is sent to the centers of the nervous system that respond to sweetness, causing humans to taste sweet. But what causes people to rank the sweetness of the same samples differently because of tasting the sweetness differently is that a person might have more taste buds and therefore more taste cells or they might respond to the sweet signal differently.

This lab’s main focus was to learn about how the structure of a carbohydrate can affect its taste, and how it ultimately affects the cell or organism.

http://www.npr.org/2011/03/11/134459338/Getting-a-Sense-of-How-We-Taste-Sweetness (Dr. Robert Margolskee’s interview)